Clutch backer plate with recessed rivets

ABSTRACT

A driven disc assembly is provided wherein a clutch disc has enlarged holes for connection of opposing backing plates. The backing plates have semi-pierced sections that are insertable within mounting holes of the clutch disc. The thickness of the backing plates are enlarged from their normal thickness causing a top surface of the backing plates to axially clear heads of conventional rivets. The thickness of the friction buttons on the backing plates can then be reduced to their minimal effective use thickness.

FIELD OF THE INVENTION

The field of the present invention is that of friction or driven discassemblies. The present invention is particularly applicable in drivendisc assemblies in clutches utilized to selectively connect an engine ofa motorized vehicle with a transmission of the motorized vehicle,especially vehicles such as large trucks.

BACKGROUND OF THE INVENTION

Many large motorized vehicles have a clutch assembly to selectivelyconnect an engine of the vehicle with the vehicle transmission. Theworkings of such a clutch assembly can be discovered by a review of U.S.patent application Ser. No. 12/807,971, Franke, entitled Dry ClutchHaving Solid Lubricant Friction Stabilization Inserts, filed Sep. 17,2010 (the disclosure of which is incorporated by reference herein).Referring to FIGS. 1, 7 and 11, a conventional driven disc assembly 9includes a disc member 11. The disc member 11 is torsionally connectedwith a damper unit 13 which spring dampens torsional vibrationsdelivered to an input shaft of a transmission. The disc member 11 istypically a thin metallic plate having along it's periphery a series ofblades or wings 15. The wings 15 on opposing faces have connectedthereto a friction pad 17. The friction pad 17 consists of a backingplate 19 with a connected friction material, commonly a ceramic frictionmaterial 21. The friction material 21 is referred to as the button inmany applications. The friction pads 17 are connected to the frictiondisc 11 by a series of flathead semi-tubular rivets 23. Referring theaddition to FIG. 11, the flathead semi-tubular rivets 23 have apurchased head 25 and a peened head 27 formed by an assembly operation.

The overall axial width 29 (adjacent its outer diameter) of the drivendisc assembly 9 based upon the design of the driven disc assembly 9 anda clutch intermediate plate and/or clutch cover assembly that the drivendisc assembly interacts with. The overall axial width (sometimes alsoreferred to as height) of the buttons 21 is determined by two factors.The first factor is the expected wear life of the button and isdetermined by a dimension 31. The second dimension is a dimension 33that is a width of the friction material on the backing plate requiredfor clearance of the rivet head 27 (or on the other side 25).Accordingly, the amount of friction material of a width 33 isessentially wasted material that cannot be utilized. Typically, theceramic material making up the button is a very expensive material thattypically far exceeds the cost of the backing plate 19. The backingplate is typically a metallic material.

One attempt to eliminate or to make more use wasted button material isprovided in FIGS. 6 and 10. In FIGS. 6 and 10, a recessed rivet drivendisc assembly 41 is provided. In the driven disc assembly 41, thebacking plates 43 have adjacent to the rivet holes recesses 45. Becauseof the recesses 45, a specialty axially shortened rivet 47 is utilized.The driven disc assembly 41 in FIGS. 6 and 10 does provide an advantageof shortening the rivet, allowing a greater portion of the buttons 48 tobe utilized. However, since the overall thickness 29 of the driven discassembly is determined by other design criteria, the recessed design ofdriven disc assembly 41 mandates even thicker buttons 48 (to achieve anoverall axial thickness 29) thereby providing a button with more excessmaterial which cannot be utilized (due to clutch design) and therebyincreasing driven disc assembly cost.

Referring to FIGS. 2 through 5 and 9, an alternative design driven discassembly 61 has been put forth. Driven disc assembly 61 has an overallaxial width 29. In driven disc assembly 61, the disc 11 can be utilized.Driven disc assembly 61 has a backing plate 63 that has an elevated flatsection 67 that is elevated by a series of dimple mounds 69. The dimplemounds 69 raise an outer surface of the backing plate 63 outward so thatthe button 71 can have an effective thickness 31 thereby eliminating thenon-utilized thickness 33 of the button in the conventional used drivendisc assembly 9. Although this design did provide the advantages desiredin reduction of friction material utilized, the non-flat contact betweenthe section 67 of the backing plate with the disc caused the backingplate 63 to buckle due to the lack of adequate heat transfer from thebacking plate 63 to the disc 11.

It is desirable to provide a driven disc assembly wherein the thicknessof the friction button can be reduced to its effective use to minimizethe costs of the driven disc assembly without compromising operationalperformance.

SUMMARY OF THE INVENTION

To meet the above-noted and other desires, a revelation of the presentinvention is brought forth. The present invention brings forth a drivendisc assembly wherein the clutch disc has enlarged holes for connectionof the backing plates. The backing plates have semi-pierced sectionsthat are insertable within the clutch disc holes. The thickness of thebacking plates are enlarged from their normal thickness causing a topsurface of the backing plates to axially clear the head of aconventional rivet. The thickness of the friction buttons can then bereduced to their minimal effective thickness.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein: TAPE 1

FIG. 1 is a partial perspective view of a conventional driven discassembly;

FIG. 2 is a perspective view of a prior art backing plate having adimple or quilted surface which is an alternative to a backing plateshown in FIG. 1;

FIG. 3 is another perspective view of the same backing plate shown inFIG. 2;

FIG. 4 is a partial perspective view of the backing plate shown in FIGS.2 and 3 assembled to a disc to partially illustrate a driven discassembly;

FIG. 5 is a view of a backing plate shown in FIGS. 2-4 wherein thebacking plate is turned upside down to illustrate its dimples;

FIG. 6 is a perspective view shown partially in section of a prior artdriven disc assembly which is an alternative to the conventional drivendisc assembly shown in FIG. 1;

FIG. 7 is a perspective view partially sectioned of the conventionaldriven disc assembly shown in FIG. 1;

FIG. 8 is a perspective view of a preferred driven disc assemblyaccordingly to the present invention;

FIG. 9 is a sectional view of the driven disc assembly shown in FIGS.2-5;

FIG. 10 is a sectional view of the driven disc assembly shown in FIG. 6;

FIG. 11 is a sectional view of a conventional driven disc assembly shownin FIGS. 1 and 7; and

FIG. 12 is an enlarged side sectional view of the preferred embodimentdrive disc assembly shown in FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

Referring to FIGS. 8 and 12, an inventive low profile button dual faceclutch friction plate or disc driven assembly 107 has an overall axialwidth 29. The disc driven assembly 107 has a disc 111. The disc 111 hasa series of mounting holes 114, which are enlarged in comparison to themounting holes shown formed in the disc drive assembly 9 disc 11.However, in other aspects, the disc 111 is essentially identical to thedisc 11. A backing plate 116 is provided which typically has a greaterthickness 136 (typically a total thickness between 0.080 and 0.110inches) than the backing plates previously described. The backing plate116 has a mounting hole 118. Hole 118 is smaller in diameter then thedisc hole 114 and is aligned therewith. The hole 118 is surrounded by astamped semi-pierced section 120. An axially inner section 122 of thesemi-pierced section 118 is inserted within the clutch disc holes 114.There is an axial gap 124 between inner axially extreme portions 127 ofthe opposing backing plates. A lateral abutting contact thickness 126 ofthe semi-pierced section to the rivet 23 is greater than a thickness 31(typically between 0.040 and 0.075 inches) of the friction button 128.Due to the increased thickness of backing plates 116, the backing plates116 provide a major flat surface section 130 in adjacent contact withthe friction button 128 that is beyond or above the heads 27 or 25 ofthe rivets 23 (identical to the rivets 23 utilized in the driven discassembly 9 shown in FIG. 11). The gap 124 between the extreme axiallyextreme ends 127 of the backing plates ensure that the rivets hold thetwo backing plates 116 in maximum tension after assembly to the disc111.

Between the semi-pierced section 120 of the backing plates and themounting hole 114 of the disc is an installation gap 134. Theinstallation gap is primarily to ensure the proper clearance needed forthe assembly operation. The semi-pierced section 120 has an abuttinglateral contact interface 131 with a tubular portion 133 of the rivet.The length of the lateral abutting contact of the semi-pierced sectionwith the rivet noted as width 126 is greater than the width 31 of thebutton 128. The contact section 120 along its outer diameter has anabutting lateral interface 139 of an axial width 140. The axial width140 in most instances will be at least equal or greater than the width31 of the button minus 0.035 inches (or the width of the button 128 isno more than 0.035 inches more than that of the width 140) and in mostapplications will be between 0.040 to 0.055 inches in total width. Theradial width 138 of the semi-pierced portion in most instances will begreater than the radial width 135 of the tubular wall 133 of the rivet.Due to the abutting lateral interface 139 of the semi-pierced portions120 with the disc hole 114 and also due to the fact that the radialwidth 138 of the semi-pierced portion 120 is greater than the radialwidth of the rivet 135, the sheer strength of the connection of thebacking plate 116 to the disc 111 is significantly greater than thesheer strength of the connection of the backing plates 119 to the disc11 of the driven disc assembly 9 which is the conventional design.

The description of the invention is merely exemplary in nature and,thus, variations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

What is claimed is:
 1. A low profile button dual face clutch frictionplate comprising: a clutch disc having mounting holes formed therein;opposed faced backing plates for connection with said disc, said backingplates having a major flat surface section adjacent said disc, saidbacking plates having smaller diameter holes aligned with said discholes with semi-pierced sections surrounding said backing plates holes,an axially inner section of said semi-pierced sections being insertedwithin said clutch disc mounting holes and wherein there is a gapbetween axial extreme portions of said opposing backing plates; flatheadsemi-tubular rivets having tubular bodies closely adjacent said holes ofsaid backing plates with heads axially capturing said semi-piercedsections of said backing plates; and a friction button on each backingplate, said friction button having a thickness less than a thickness ofone of said backing plates.
 2. A clutch friction plate as described inclaim 1, wherein a lateral contact of said semi-pierced section of oneof said backing plates with said rivet is greater than said thickness ofsaid friction button.
 3. A clutch friction plate as described in claim1, wherein there is radial installation spacing between saidsemi-pierced section of said backing plate and said disc hole.
 4. Aclutch friction plate as described in claim 1, wherein said button has athickness between 0.040 and 0.075 inches.
 5. A clutch friction plate asdescribed in claim 1, wherein one of said backing plates has a thicknessbetween 0.080 and 0.110 inches.
 6. A clutch friction plate as describedin claim 1, wherein one of said backing plates semi-pierced section hasan abutting lateral interface with said disc thickness between 0.040 and0.055 inches.
 7. A low profile button dual face clutch friction platecomprising: a clutch disc having mounting holes formed therein; opposedfaced backing plates for connection with said disc, said backing plateshaving a major flat surface section adjacent said disc, said backingplates having smaller diameter holes aligned with said disc holes withsemi-pierced sections surrounding said backing plates holes, and axiallyinner section of said semi-pierced sections being inserted within saidclutch disc holes and wherein there is a gap between axial extremeportions of said opposing backing plates; flathead semi-tubular rivetshaving tubular bodies closely adjacent said holes of said backing plateswith heads axially capturing said semi-pierced sections of said backingplates; a friction button on each backing plate said friction buttonhaving a thickness less than a thickness of one of said backing plates;and wherein a lateral contact of said semi-pierced section of saidbacking plate with said rivet is greater, equal or no more than 0.035less than said thickness of said button and wherein there is a radialinstallation spacing between said semi-pierced section of said backingplate and said hole said disc hole.
 8. A clutch friction plate asdescribed in claim 7, wherein said button has a thickness between 0.040and 0.075 inches.
 9. A clutch friction plate as described in claim 7,wherein one of said backing plates has a thickness between 0.080 and0.110 inches.
 10. A clutch friction plate as described in claim 7,wherein one of said backing plates semi-pierced section has an abuttinglateral interface with said disc thickness between 0.040 and 0.055inches.
 11. A low profile button dual face clutch friction platecomprising: a clutch disc having mounting holes formed therein; opposedfaced backing plates for connection with said disc, said backing plateshaving smaller diameter holes aligned with said disc holes withsemi-pierced sections surrounding said backing plates holes, an axiallyinner section of said semi-pierced sections being inserted within saidclutch disc mounting holes and wherein said semi-pierced sections havean abutting lateral interface with said disc; rivets closely adjacentsaid holes of said backing plates with heads axially capturing saidsemi-pierced sections of said backing plates; and a friction button oneach backing plate, said friction button having a thickness less than athickness of one of said backing plates.
 12. A clutch friction plate asdescribed in claim 11, wherein a lateral contact of said semi-piercedsection of one of said backing plates with said rivet is greater thansaid thickness of said friction button.
 13. A clutch friction plate asdescribed in claim 11 wherein said rivet is a flathead semi-tubularrivet and wherein a radial thickness of said semi-pierced section isgreater than a radial thickness of said rivet.
 14. A clutch frictionplate as described in claim 11 wherein an abutting lateral interface ofsaid semi-pierced portion is at least within 0.035 inches of an axialthickness of said friction button.